***THREAD*** How can we compute the depth of earthquakes? Here's an example from yesterday's M7 offshore north Japan quake. Earthquakes produce P and S waves that travel through the Earth. For distant earthquakes, P-waves travel through Earth's mantle from the source to a station
Alternatively, seismic energy may travel up to the surface of the Earth first, then bounce-back (reflect) off the surface, travelling back down into the Earth, and along the usual direct path through the mantle. We call these seismic arrivals "depth phases".
Depth phases are great because the extra time it takes for the seismic energy to go up and down from the surface reflection is directly related to the earthquake's depth. We count how much extra time the depth phases arrive after the direct phase that goes all through the mantle.
Following a magnitude 2.9 earthquake induced by hydraulic fracturing (“fracking”) for shale gas in northern England in August this year, it seems that the UK government will announce tomorrow an indefinite ban on all fracking operations and plans.
Full news article here: theguardian.com/environment/20…
Political backdrop: yes there is a general election coming up, and all other main political parties have said they will ban fracking, but this decision does appear to have some scientific basis based on the latest data & research.
You can find copies of the regulators’ report as well as those of other scientific groups here: ogauthority.co.uk/onshore/onshor….
Will try to unpick some of the main findings over the course of the day (thread coming up).
Back from adventurous holidays in the absolutely fabulous mountains of the Italian Dolomites.
I deleted the Twitter app which felt very refreshing - it’s worth taking a break now and again to make you feel more “in the moment” and absorb stunning scenery like this 👇
We spent most of our time climbing mountains using “via ferrata”, which translates to “The Iron Way” - a series of in-situ steel cables and ladders to assist with climbing. Routes can be exposed and steep, but it is a safe way to explore the mountains with quite a bit of freedom
Whilst now used for leisure, the original Via Ferrata routes were put up during World War 1, with the Italian and Austria-Hungarian troops digging in and fighting to siege control of the mountainous region. You can now explore the original tunnels and trenches through mountains
THREAD - so here is a list of the 5 or so most common myths and misconceptions by the general public and fellow non-specialist scientists alike that I encounter in my field of research. #mythbusting#Factchecking
*MYTH No. 1*: the time, location and size of impending earthquakes can be predicted accurately on many occasions.
No. Anyone who says they can is a total charlatan. Forecasting (years->decades) is getting better, but still not successful on short timescales (i.e. days to months)
*MYTH No. 2*: Seismic monitoring networks and government agencies hide seismic data & earthquake parameters from the public.
No. Anyone who says so is a paranoid conspiracy theorist. It is in no one's interest to hide this data and scientists aren't the best at keeping secrets.
Sorry, Angus Energy, but some of the science and facts on your "FAQs: Surrey Tremors page" doesn't completely add up.
Thread below. angusenergy.co.uk/media/faqs-sur…
1. The shaking intensity felt during the largest earthquakes in the swarm wasn't "the lowest intensity possible". Actually, shaking intensity of level 4 on the European Macroseismic Scale was felt during the 05/07 event and reported by the BGS earthquakes.bgs.ac.uk/earthquakes/re…
This shaking intensity scale goes from 1 (Not Felt) to 12 (Completely Devastating) Other earthquakes in the sequence had ground shaking intensities of level 3; other earthquakes in the swarm were not felt. Shallow depth of earthquakes = higher shaking intensity over a small area.